I've got a new radio/CD coming this week. I think I'm comfortable with the process of taking the old unit out, and putting the new one in.....but.....

It's got a DAB (might be called dish or digital or something else in the US ) and has a separate aerial for that bit. That aerial is supposed to be mounted on the windscreen. I think it can tuck neatly in the corner.
How am I going to get the cable for that from the back of the radio, to come out near the windscreen?

Any advice would be very much appreciated.